A bass drum is very a popular music instrument for producing extreme percussive bass sound. FIG. 4 shows a conventional pedal 10 for a bass drum (not shown). The pedal 10 comprises a foot plate 12 which has an end pivotably mounted on a base of the pedal 10 and another end pivotably connected with a linkage 14, a mounting block 16 which defines a socket 162 for receiving an end of a beater (not shown) which is drivably connected with the linkage 14 through a shaft 18 which is used to rotatably support the mounting block 16 on a bearing means. When the foot plate 12 is stepped on by a foot of a user, the mounting block 16 will have a pivotable movement with the shaft 18 about the bearing means to make the beater strike on a head (not shown) of the drum to generate bass sound.
Furthermore, the conventional pedal 10 comprises a clamping mechanism generally indicated by reference number 20 to attach the pedal 10 to a counterhoop 60 (FIGS. 6 and 7) of the bass drum.
Also referring to FIG. 5, the clamping mechanism 20 comprises a frame 30 defining a counterhoop receiving seat 32 and two upright walls 34 spacing from each other a distance. Each wall 34 defining a hole 342 to allow a pin 48 to extend therethrough. A pressing plate 40 is pivotably mounted on the pin 48 by extending the pin 48 through a hole 401 horizontally defined in the pressing plate 40 and the holes 342 of the upright walls 34. A clamping block 50 is fixedly mounted on a bottom of the pressing plate 40 and located near a front end thereof by extending a screw 42 through a countersink 402 vertically defined in the pressing plate 40 to threadedly and fixedly engage in a periphery defining a hole 502 in the clamping block 50. A bolt 44 which has a handle 46 fixedly connected therewith is threadedly connected with the pressing plate 40 on a rear end thereof. When the handle 46 is turned to rotate the bolt 44 about the pressing plate 40 to lift the rear end of the pressing plate 40 along the bolt 44, the front portion of the pressing plate 40 and, thus, the clamping block 50 will have a downward movement since the pressing plate 40 is pivotably mounted on the upright walls 34 via the pin 48. Thus, the clamping block 50 can exert a clamping force on the counterhoop 60 (FIGS. 6 and 7) of the bass drum to attach the pedal 10 to the bass drum.
However, the clamping mechanism 20 of the conventional pedal 10 has the following disadvantages, which will be explained in detail in reference to FIGS. 6 and 7.
Generally, the thickness of the counterhoop of a bass drum is ranged from 9 mm to 10 mm. When the counterhoop 60 which has a large thickness, for example 10 mm as shown in FIG. 6, is pressed between the receiving seat 32 and the clamping block 50, due to the clamping block 50 being fixedly attached on the pressing plate 40 and the geometry relationship between the counterhoop 60 and the clamping block 50, only a rear portion of the clamping block 50 can effectively engage with the counterhoop 60. Alternatively, when the counterhoop 60, which has a small thickness, for example 9 mm as shown in FIG. 7, is pressed between the receiving seat 32 and the clamping block 50, based on the same reasons as mentioned above, only a front portion of the clamping block 50 can effectively engage with the counterhoop 60. In both of the above two situations, the clamping mechanism 20 can not very firmly clamp the counterhoop 60, so that after a period that the beater has struck on the head of the drum, the pedal 10 may detach from the bass drum.